Thanks, Shane. Can you also link to this mailing list discussion from the JIRA ticket?
-- Reynold Xin, AMPLab, UC Berkeley http://rxin.org On Sat, Sep 21, 2013 at 9:01 PM, Shane Huang <[email protected]>wrote: > I summarized the opinions about Config in this post and added a comment on > SPARK-544. > Also post here below: > > 1) Define a Configuration class which contains all the options available > for Spark application. A Configuration instance can be de-/serialized > from/to a formatted file. Most of us tend to agree that Typesafe Config > library is a good choice for the Configuration class. > 2) Each application (SparkContext) has one Configuration instance and it is > initialized by the application which creates it (either coded in app (apps > could explicitly read from io stream or command line arguments), or system > properties, or env vars). > 3) For an application the overriding rule should be code > system > properties > env vars. Over time we will deprecate the env vars and maybe > even system properties. > 4) When launching an Executor on a slave node, the Configuration is firstly > initialized using the node-local configuration file as default (instead of > the env vars at present), and then the Configuration passed from > application driver context will override specific options specified in > default. Certain options in app's Configuration will always override those > in node-local, because these options need to be the consistent across all > the slave nodes, e.g. spark.serializer. In this case if any such options is > not set in app's Config, a value will be provided by the system. On the > other hand, some options in app's Config will never override those in > node-local. as they're not meat to be set in app, e.g. spark.local.dir > > > On Wed, Sep 18, 2013 at 1:42 AM, Matei Zaharia <[email protected] > >wrote: > > > Hi Shane, > > > > I agree with all these points. Improving the configuration system is one > > of the main things I'd like to have in the next release. > > > > > 1) Usually the application developers/users and platform administrators > > > belongs to two teams. So it's better to separate the scripts used by > > > administrators and application users, e.g. put them in sbin and bin > > folders > > > respectively > > > > Yup, right now we don't have any attempt to install on standard system > > paths. > > > > > 3) If there are multiple ways to specify an option, an overriding rule > > > should be present and should not be error-prone. > > > > Yes, I think this should always be Configuration class in code > system > > properties > env vars. Over time we will deprecate the env vars and maybe > > even system properties. > > > > > 4) Currently the options are set and get using System property. It's > hard > > > to manage and inconvenient for users. It's good to gather the options > > into > > > one file using format like xml or json. > > > > I think this is the main thing to do first -- pick one configuration > class > > and change the code to use this. > > > > > Our rough proposal: > > > > > > - Scripts > > > > > > 1. make an "sbin" folder containing all the scripts for > administrators, > > > specifically, > > > - all service administration scripts, i.e. start-*, stop-*, > > > slaves.sh, *-daemons, *-daemon scripts > > > - low-level or internally used utility scripts, i.e. > > > compute-classpath, spark-config, spark-class, spark-executor > > > 2. make a "bin" folder containing all the scripts for application > > > developers/users, specifically, > > > - user level app running scripts, i.e. pyspark, spark-shell, and > we > > > propose to add a script "spark" for users to run applications > (very > > much > > > like spark-class but may add some more control or convenient > > utilities) > > > - scripts for status checking, e.g. spark and hadoop version > > > checking, running applications checking, etc. We can make this a > > separate > > > script or add functionality to "spark" script. > > > 3. No wandering scripts outside the sbin and bin folders > > > > Makes sense. > > > > > - Configurations/Options and overriding rule > > > > > > 1. Define a Configuration class which contains all the options > > available > > > for Spark application. A Configuration instance can be de-/serialized > > > from/to a json formatted file. > > > 2. Each application (SparkContext) has one Configuration instance and > > it > > > is initialized by the application which creates it (either read from > > file > > > or passed from command line options or env SPARK_JAVA_OPTS). > > > 3. When launching an Executor on a node, the Configuration is firstly > > > initialized using the node-local configuration file as default. The > > > Configuration passed from application driver context will override > any > > > options specified in default. > > > > This sounds great to me! The one thing I'll add is that we might want to > > prevent applications from overriding certain settings on each node, such > as > > work directories. The best way is to probably just ignore the app's > version > > of those settings in the Executor. > > > > If you guys would like, feel free to write up this design on SPARK-544 > and > > start working on it. I think it looks good. > > > > Matei > > > > > -- > *Shane Huang * > *Intel Asia-Pacific R&D Ltd.* > *Email: [email protected]* >
